It is known to provide a driver selectable Economy Mode (Eco-Mode) to enable a driver to bias the performance/fuel economy relationship in favor of fuel economy. One known Eco-Mode feature is to limit the maximum speed that a vehicle can travel at but such a feature does not have any positive impact on fuel economy during an acceleration phase of the motor vehicle. In order to address the need for reducing fuel consumption during the acceleration phase it is also known to provide an indication to a driver of the desired (e.g., optimum) gear-based engine speed for an up-shift via a Shift Indication Light (SIL) sometimes referred to as a gear shift indicator (GSI).
It is a problem with such GSI devices that it is left up to driver of the motor vehicle to decide whether to follow the recommended shift schedule as provided by the GSI or not. If the driver regularly ignores the GSI then there will be very little reduction in fuel usage and so there is a risk that customers will be dissatisfied with the fuel economy benefit obtained when using an Eco-mode of operation. Therefore finding the right balance between performance degradation and improved fuel economy is essential if a driver is to realize the benefit of selecting an ECO-mode of operation.
To overcome at least some of the aforementioned problems, a method for reducing the amount of fuel used by an engine of a motor vehicle having a transmission providing a number of forward ratios selectable by the driver of the motor vehicle is provided. The method includes, when one of the speed of the engine and the road speed of the vehicle reaches a predefined upper speed limit for the currently selected gear, controlling one of the speed of the engine and the road speed of the vehicle to maintain the speed at a speed substantially equal to the predefined upper speed limit for the currently selected gear and providing an indication to a driver of the motor vehicle that the selection of a higher gear ratio is required in order to increase fuel economy.
The above advantages and other advantages, and features of the present description will be readily apparent from the following Detailed Description when taken alone or in connection with the accompanying drawings.
It should be understood that the summary above is provided to introduce in simplified form a selection of concepts that are further described in the detailed description. It is not meant to identify key or essential features of the claimed subject matter, the scope of which is defined uniquely by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure. Additionally, the above issues have been recognized by the inventors herein, and are not admitted to be known.